WO2005103585A1

WO2005103585A1 - Device and method for generating thermal units with magnetocaloric material

Info

Publication number: WO2005103585A1
Application number: PCT/IB2005/001059
Authority: WO
Inventors: Christian Muller; Jean-Louis Dupin; Jean-Claude Heitzler
Original assignee: Cooltech Applications
Priority date: 2004-04-23
Filing date: 2005-04-21
Publication date: 2005-11-03
Also published as: KR101215702B1; EP1740892A1; JP5027653B2; CN1946976A; JP2007533949A; DK1740892T3; EA200601740A1; PL1740892T3; DE602005004272T2; ZA200608704B; AU2005236244B2; FR2869403A1; HK1099802A1; ES2300003T3; KR20070017152A; CA2562496C; MXPA06012099A; CN100436967C; AU2005236244A1; HRP20080162T3

Abstract

The invention relates to a device for generating thermal units with magnetocaloric material that consumes low amounts of energy, is expandable, has a simple design, operates reliably, and enables the generation of thermal units in an economical manner while eliminating the risks of thermal liquid leaks and limiting the number of mechanical parts. The device (1a) for generating thermal units with magnetocaloric material comprises: a magnetic element (2a) coupled to an electrical power supply (3a); a magnetocaloric element (4a); a heat transfer fluid circuit (5) in which one or more heat transfer fluids are circulated by circulating means (6), and; two heat exchangers (7, 8). The electrical power supply (3a) is provided for generating electrical pulses in order to create a pulsed magnetic field that causes the heating and cooling of the magnetocaloric element (4a) and thus the heat transfer fluid. The invention is used as a heat exchanger for cooling, heating, air-conditioning and regulating temperature.

Description

DEVICE AND METHOD FOR GENERATING THERMAL MAGNETO-CALORIC MATERIAL

Technical area :

The present invention relates to a thermo-caloric material thermal generating device comprising at least one magnetic element for generating a magnetic field, at least one magneto-caloric element intended to be alternately subjected to said magnetic field to generate calories and of frigories, at least one coolant circuit of which at least a portion is disposed in the immediate environment of the magneto-caloric element so as to recover at least a portion of the calories and / or frigories that it emits, said circuit being coupled to means for circulating the coolant and at least one heat exchanger arranged to transfer at least a portion of the calories and / or frigories recovered by said heat transfer fluid. The invention also relates to a method of generating thermies using said device.

Prior art:

In known manner, thermal generators magneto-caloric material comprise fixed magnetic means and magneto-caloric movable elements coupled to displacement means, or vice versa. Thus, the magneto-caloric elements are alternately subjected to the presence and the absence of a magnetic field and generate alternately calories and frigories. These thermals are recovered by heat transfer fluids passing through the magneto-caloric elements and connected to "hot" and "cold" circuits comprising heat exchangers for heating and / or cooling and / or tempering and / or cooling for example an ambient medium, an enclosure, a room, the interior of a container.

C0PY TION In the case where the magneto-caloric elements are movable relative to the magnetic means, it is very difficult to ensure good sealing between the sections passing through the magnetocaloric elements and the circuits "hot" and "cold" and leaks are common .

The magnetic means generally comprise a magnetic assembly, a permanent magnet, an electromagnet, a superconducting magnet, a superconducting electromagnet, a superconductor. Permanent magnets do not make it possible to obtain satisfactory results in terms of magnetic power. Compared to this criterion, the best results are obtained by electromagnets and electromagnets superconductors. Unfortunately, electromagnets are very large consumers of electrical energy which makes them expensive to use. In addition, they heat up quickly and the evacuation of their calories complicates the construction of thermal generators. In addition, the technique of superconducting electromagnets is very expensive.

On the other hand, the use of electromagnets makes it possible to vary their magnetic field by supplying them with a variable electric current. This solution has the advantage of eliminating any relative movement between the magnetocaloric elements and the magnetic means. Publications FR-A-2 574 913, EP-A-0 104 713 and US Pat. No. 6,595,004 describe examples of variable current power supplies, some of which are limited to superconducting electromagnets not compatible with the present invention. Similarly, the variable current power supply does not provide satisfactory results in terms of energy consumption and cost.

The existing solutions are therefore not satisfactory.

Presentation of the invention The present invention aims to overcome these drawbacks by proposing a device for generating energy magneto-caloric material low energy consuming, scalable, simple design, reliable operation, allowing the generation of thermies in a cost-effective manner while removing the risks of thermal fluid leakage and limiting the number of mechanical parts.

For this purpose, the invention relates to a device for generating thermals of the type indicated in the preamble, characterized in that the magnetic element is an electromagnet coupled to at least one electrical power supply servocontrolled by at least one control unit arranged to generate electrical pulses so as to create a pulsed magnetic field, these electrical pulses of intensity I, of duration t and of frequency T being triggered as a function of at least one predetermined pulse parameter, said device comprising at least one arranged thermal sensor for determining the temperature of said heat transfer fluid, said fluid temperature defining at least one pulse parameter.

The recovery means preferably comprise at least two heat exchangers connected to the circuit in series, in parallel or in a series / parallel combination.

Preferably, the recovery means comprise at least one caloric heat exchanger arranged for transferring the calories and at least one cold heat exchanger arranged to transfer the frigories, the heat exchangers being coupled to switching means servocontrolled by a control unit. control arranged to successively connect each heat exchanger to the magnetocaloric element as a function of at least one predetermined switching parameter. The control unit may be arranged so that the frequency T is between 60 seconds and ^1/50 seconds and preferably less than 2 seconds.

The control unit may also be arranged so that the ratio T / t is between 10 and 100,000, and preferably greater than 1,000.

The control unit may finally be arranged so that the intensity I generates in the magnetic element a magnetic field between 0.05 Tesla and 10 Tesla, and preferably greater than 2 Tesla.

According to a preferred embodiment, the control unit comprises means for adjusting at least one of the parameters of the electrical pulse selected from the group comprising the duration t, the frequency T, the intensity I.

According to a preferred embodiment, the control unit comprises delay means arranged to determine 1 time interval since switching and / or 1 previous electric pulse, this time interval defining at least one switching parameter and / or impulse.

For this purpose, the control unit may comprise means for adjusting the switching parameter and / or the predetermined pulse.

The recovery means advantageously comprise at least one "mixed" exchanger arranged to transfer the calories and the frigories, for example, into the ambient environment.

The device preferably comprises at least two magneto-caloric elements connected together in series, in parallel or in a series / parallel combination, the magneto-caloric elements may have different magnetocaloric characteristics.

Advantageously, the device comprises at least two electromagnets, each associated with a magneto-caloric element and at least two electrical power supplies arranged to electrically power the electromagnets in a dissociated manner.

Preferably, the core of said electromagnet is made of a magnetic material with high remanence.

The magnetic element and the magneto-caloric element are preferably fixed relative to each other.

The invention also relates to a method of generating thermies in which the previous device is used.

During this process, at least two magnetocaloric elements can be used, each associated with an electromagnet, and at least two electrical power supplies, and, in successive phases, using a first magneto-caloric element alone and then a first and a second magneto-caloric element simultaneously and finally the second magnetocaloric element alone so as to combine the magnetocaloric properties of the first and second magneto-caloric elements.

Brief description of the drawings:

The present invention and its advantages will appear better in the following description of several embodiments with reference to the appended drawings given as non-limiting examples, in which: FIG. 1 is a schematic view of the device according to the invention, FIGS. 2A and 2B are curves illustrating the operation of the device of FIG. 1 respectively according to the cooling and heating modes, FIG. 3 is a schematic view of a first variant. embodiment of the device according to the invention,

FIG. 4 is a curve illustrating a mode of operation of the device of FIG. 3, FIG. 5 is a schematic view of a second variant embodiment of the device according to the invention, FIGS. 6A and 6B are curves illustrating the operation. of the device of Figure 5 respectively according to the cooling and heating modes, and Figure 7 is a diagram of the control unit of the device according to the invention.

Illustrations of the invention:

For the sake of simplification, the terms "device" and "process" will be used to replace the terms "device for generating thermics with magnetocaloric material" and "method for generating magnies with magneto-caloric material".

Furthermore, the term "heat exchanger" means any means for the transfer and / or diffusion of calories and / or frigories. With reference to FIG. 1, the device 1a comprises a magnetic element 2a coupled to a power supply 3a, a magnetocaloric element 4a, a heat transfer fluid circuit 5 in which one or more heat transfer fluids are circulated by means of circulation 6, and two heat exchangers 7, 8.

The magneto-caloric element 4a contains a magneto-caloric material such as, for example, gadolinium (Gd), a gadolinium alloy comprising silicon (Si), germanium (Ge), iron (Fe), magnesium (Mg ), phosphorus (P), arsenic (As) or any other equivalent material. This magneto-caloric material is for example in the form of a block, pellets, powder, agglomerate, pieces.

The magneto-caloric characteristics of the magneto-caloric element 4a are such that: - when it is subjected to the presence of a magnetic field, the magnetocaloric element 4a heats up under the magneto-caloric heating effect, and that, when the magnetic field disappears or decreases, the magneto-caloric element 4a continues to heat up under the effect of the magnetocaloric inertia, and, after exhausting this magneto-caloric inertia, the magnetocaloric element 4a cools to a temperature below its initial temperature under the magneto-caloric cooling effect. The operating principle of the device therefore consists in subjecting the magneto-caloric element 4a to a variation of magnetic field to generate calories and frigories used to heat, cool, cool, temper, an enclosure, an ambient environment, etc.

To do this, the magnetic element used is an electromagnet 2a that is placed in the environment close to the magnetocaloric element 4a so that it is subjected to the magnetic field. The electromagnet 2a is electrically energized at means of a power supply 3a generating a pulse electric current so as to obtain a modification of the magnetic field. The magnetocaloric element 4a thus subjected to a pulsed magnetic field generates calories and frigories. An electromagnet 2a whose magnetic core is made of a high-persistence magnetic material, such as, for example, cobalt iron alloys, rare earths, ferrites, iron and silicon alloys, iron, nickel.

These calories and frigories are recovered by the coolant circulating in the portion of the heat transfer fluid circuit 5 disposed in the immediate environment of the magnetocaloric element 4a. The magneto-caloric element 4a is for example traversed by this portion. The circuit 5 is made for example in a traditional manner by assembling pipes or by any other suitable means. The circuit 5 comprises circulation means 6 of the heat transfer fluid such as for example a pump or any other equivalent means.

In this example, the power supply 3a is controlled by a control unit 20 (see Fig. 7) generating successive electric pulses 9a of intensity I, of duration t, at a frequency T, these characteristics being adjustable.

These electrical pulses 9a are generated as a function of one or more predetermined pulse parameters, for example as a function of the temperature of the coolant and / or the time interval elapsed since the previous electric pulse 9a. For this purpose, the device la comprises a thermal sensor 10 and / or delay means (not shown).

The thermal sensor 10 makes it possible to determine the temperature of the coolant, for example at the outlet of the magnetocaloric element 4a. This determination is carried out in an absolute manner for example by measuring in degrees, by detecting a temperature threshold or, relative by comparison, for example in degrees, with respect to another temperature. The determined temperature is compared with a predetermined temperature setpoint. When the temperature setpoint is reached, 1 electric pulse 9a is generated.

The delay means make it possible to determine an elapsed time interval, for example, from the previous electric pulse 9a and to compare it with a predetermined time setpoint. When the time setpoint is reached, 1 electrical pulse 9a is generated. The delay means are for example electronic circuits, pneumatic circuits, a combination of electronic and pneumatic circuits or any other known means.

In this example, the device la comprises a heat exchanger 7 for transferring calories and a heat exchanger 8 for transferring the frigories. These heat exchangers 7, 8 are connected in parallel to the heat transfer fluid circuit 5 by switching means 11 controlled by a control unit, which can be the same as that which slaves the power supply 3a, and which makes it possible to successively connect each heat exchanger 7, 8 to the magnetocaloric element 4a.

This switching is performed as a function of one or more predetermined switching parameters, for example as a function of a time interval elapsed since one electric pulse 9a and / or since the previous switching and / or as a function of the temperature of the coolant. . For this purpose, the control unit comprises delay means and / or a thermal sensor 10.

The delay means and / or the thermal sensor 10 may be the same as the previous ones. When the time setpoint and / or the temperature setpoint is reached, the switching means 11 put in communication the magneto-caloric element 4a with a heat exchanger 7 then with the other 8. These switching means 11 comprise for example a valve, a drawer electrically controlled, pneumatic, hydraulic , a switch or any other suitable means.

It is obvious that the control unit 20 may comprise several thermal sensors 10 and / or several delay means and / or use another pulse and / or switching parameter.

Limited control 20 shown schematically in Figure 7 is given by way of non-limiting example. It comprises a power stage powered by the 220 or 380 V sector through a transformer followed by a rectifier, a switching power supply and protections against short circuits, overloads and phase reversals. It also comprises a calculation unit controlled by at least three data: the temperature of the coolant measured by the temperature sensor 10, a temperature set point Te and the operating mode is in heating mode or in refrigeration mode. This computing unit generates three data: the duration t of the electrical pulses and their frequency T as well as their intensity I. The intensity I supplies the power stage while the duration t and the frequency T feed a time base coupled to an electric pulse generator, for example of the transistor, triac, tyrist, lamp, induction, discharge, current blocking type and preferably a transistors power electric pulse generator. The generated electrical pulses 9a are transmitted to the power stage through a shaping module, before supplying the electromagnet 2a through an output interface. The different modules entering this control unit 20 are not detailed since they are part of the normal knowledge of an electronics engineer. The method using this device is described with reference to the "Curve I" and "Curve θ" of the heat transfer fluid curve curves illustrated in FIGS. 2A and 2B, respectively in "cooling" and "heating" modes.

In "cooling" mode illustrated by the curves of FIG. 2A, the process is broken down into several successive cycles each comprising several successive steps. Cycle 1 (start): Preparation: The switching means 11 are positioned so that the magnetocaloric element 4a is connected to the heat exchanger 7. Start: The electromagnet 2a is powered by an electric pulse 9a. of intensity I which generates in the electromagnet 2a a magnetic field of between 0.05 Tesla and 10 Tesla, and preferably greater than 2 Tesla, of duration t between 10 ^-9 seconds and 60 seconds and preferably less than 10 Tesla. 10 ^"2 seconds. Step 1 - Cycle 1: During the electric pulse 9a, the electromagnet 2a generates a magnetic field. The magneto-caloric element 4a subjected to this magnetic field undergoes the magneto-caloric heating effect and heats up. The heat transfer fluid passing through the magnetocaloric element 4a is subjected to this heating and is thus heated to a temperature θ11 (temperature step 1 cycle 1) greater than the initial temperature 001. The coolant is transported to the heat exchanger 7 which transfers the calories into the environment. Step 2 - Cycle 1: After the electric pulse 9a, the electromagnet 2a is no longer electrically powered and no longer generates a magnetic field. The magneto-caloric element 4a continues to heat up, subjected to 1 inertia of the magneto-caloric heating effect. The heat transfer fluid passing through the magnetocaloric element 4a thus continues to be heated up to a temperature 021 (temperature step 2 cycle 1) greater than the temperature 011 and corresponding to the maximum temperature of the heat transfer fluid during this cycle 1. The heat transfer fluid is transported to the heat exchanger 7 which transfers the calories to the ambient environment. Step 3 - cycle 1: The inertia of the magneto-caloric heating effect ceases. The magneto-caloric element 4a, subjected to the absence of a magnetic field, undergoes the magneto-caloric effect cooling and cools. The coolant passing through the magneto-caloric element 4a is subjected to its cooling and is thus cooled to a temperature 031 (temperature step 3 cycle 1) lower than the temperature 021. The coolant is transported to the heat exchanger 7 which transfers the calories to the environment. When: - the delay means detect that 1 time interval elapsed since the previous electric pulse 9a, or - the thermal sensor 10 detects that the difference between the temperatures 031 and Θ21 or 011 or 001 of the heat transfer fluid, is equal to or lower at the switching set point C1, the switching means 11 switch and connect the magnetocaloric element 4 a to the heat exchanger 8.

Step 4 - Cycle 1: The magneto-caloric element 4a continues to cool. The coolant passing through the magnetocaloric element 4a continues to be cooled to a temperature 041 (temperature step 4 cycle 1) lower than the temperature Θ01 corresponding to the flow temperature of the heat transfer fluid during this cycle 1. The heat transfer fluid is transported to the heat exchanger 8 which transfers the frigories to the ambient environment. When: the delay means detect that the time elapsed since the previous electric pulse 9a, or the thermal sensor 10 detects that the difference between the temperatures 041 and 311 or 001 or θ11 or 021 of the heat transfer fluid is equal to or greater than at the pulse command setpoint II, limited control generates a new electrical pulse 9a which supplies the electromagnet 2a, this electric pulse 9a can be substantially similar to 1 electric pulse 9a initial or different as required. Simultaneously in this example, the switching means 11 again connect the magneto-caloric element 4a to the heat exchanger 7. It is understood that this switching can be slightly shifted in time, performed in a step 5 , so as to connect the magnetocaloric element 4a to the heat exchanger 7 only when the heat transfer fluid, under the effect of the new electric pulse 9a and the magnetic field, reaches a certain temperature.

The pulse set points In are set so that the ratio T / t of the frequency T between two electrical pulses 9a over the duration t of 1 electrical pulse 9a considered, is between 10 and 100,000, and preferably greater than 1,000. Then we go to cycle 2.

The following operating cycles are substantially similar to the first cycle and proceed as follows for the coolant: Step 1 - cycle n: During the electric pulse 9a, heating the heat transfer fluid to a temperature θln (temperature step 1 cycle in progress), higher than the temperature Θ4n-1 (temperature step 4 previous cycle) but lower than the temperature θln-1 (temperature step 1 previous cycle). Transfer of calories through the heat exchanger 7.

Step 2 - cycle n: After the electric pulse 9a, under the inertia of the magneto-caloric heating effect, heating of the coolant to a temperature Θ2n (temperature step 2 cycle in progress) greater than the temperature θln (temperature stage 1 cycle in progress) corresponding to the maximum temperature of the heat transfer fluid during this cycle, but lower than the temperature Θ2n-1 (temperature step 2 previous cycle) corresponding to the maximum temperature of the coolant during the previous cycle. Transfer of calories by the heat exchanger 7. Step 3 - cycle n: At the end of 1 inertia of the magnetocaloric heating effect, magnetocaloric cooling effect. Cooling of the heat transfer fluid to a temperature Θ3n (temperature stage 3 cycle in progress) lower than the temperature Θ2n and lower than the temperature Θ2n-1 (temperature step 2 previous cycle). Transfer of calories by the heat exchanger 7. Detection of the switching set point Cn and switching to connect the magnetocaloric element 4a to the heat exchanger 8. Step 4 - cycle n: Magnetocaloric cooling effect, cooling heat transfer fluid to a temperature Θ4n (temperature step 4 cycle in progress) lower than the temperature ΘOn and corresponding to the flow temperature of the heat transfer fluid of this cycle n. Transfer of the frigories by the heat exchanger 8. Detection of the impulse setpoint In and supply of the electromagnet 2a by a new electric pulse 9a. Simultaneously or not, switching to connect the magnetocaloric element 4a to the heat exchanger 7.

In "cooling" mode, the maximum temperatures "T upper" corresponding to Θ2n and minimum "T minimum" corresponding to Θ4n, heat transfer fluid, are becoming lower. As a result, the mean temperature "T average" of the coolant is also lower and lower, resulting in a cooling capacity and an increasing efficiency of the device and the process as the cycles of operation up to to reach the minimum cooling temperature "T Low" of the magneto-caloric element 4a at which the temperature of the heat transfer fluid will stabilize.

In "heating" mode illustrated by the curves of FIG. 2B, the process is broken down into several successive cycles substantially similar to the previous ones. This method differs from the previous one in that the values of the switching commands Cn and pulse In are different from the previous ones and chosen so as to obtain the following successive steps: Cycle 1 (start): Preparation: The switching means are positioned 11 so that the magneto-caloric element 4a is connected to the heat exchanger 7. Start: The electromagnet 2a is supplied with an electric pulse 9a of an intensity I which generates in the magnetic element a magnetic field included between 0.05 Tesla and 10 Tesla, and preferably greater than 2 Tesla, of duration t between 10 ^-9 seconds and 60 seconds and preferably less than 10 ^-2 seconds.

Cycle n: Step 1 - cycle n: During 1 electrical pulse 9a, heating of the coolant to a temperature Θln (temperature step 1 cycle in progress), greater than the starting temperature ΘO or at the temperature Θ4n-1 (temperature step 4 previous cycle) but higher than the temperature θln-1 (temperature step 1 previous cycle). Transfer of calories by the heat exchanger 7. Step 2 - cycle n: After 1 electric pulse 9a, heating of the heat transfer fluid under 1 inertia of the magneto-caloric heating effect, up to a temperature Θ2n (stage 2 cycle temperature) in progress) greater than the temperature θln (temperature stage 1 cycle in progress) corresponding to the maximum temperature of the heat transfer fluid during this cycle n, but lower than the temperature Θ2n + 1 (temperature step 2 next cycle) corresponding to the maximum temperature coolant during the next cycle. Transfer of calories by the heat exchanger 7. Step 3 - cycle n: At the end of 1 inertia of the effect of 1 heating magnetocaloric inertia, magneto-caloric cooling effect. Cooling of the heat transfer fluid to a temperature Θ3n (temperature step 3 cycle in progress) lower than the temperature Θ2n and lower than the temperature Θ2n + 1 (temperature step 2 next cycle). Transfer of calories by the heat exchanger 7. Detection of the switching set point Cn and switching to connect the magneto-caloric element 4a to the heat exchanger 8. Step 4 - cycle n: Magnetocaloric cooling effect, cooling heat transfer fluid to a temperature Θ4n (temperature step 4 cycle in progress) greater than the temperature ΘOn and corresponding to the flow temperature of the heat transfer fluid of this cycle n. Transfer of the frigories by the heat exchanger 8. Detection of the impulse setpoint In and supply of the electromagnet 2a by a new electrical pulse 9a. Simultaneously or not, switching to connect the magneto-caloric element 4a to the heat exchanger 7. In "heating" mode, the maximum temperatures "T upper" corresponding to Θ2n and minimum Θ "minimum T" corresponding to Θ4n, of the coolant, are higher and higher. As a result, the mean temperature "T average" of the coolant is also increasing, resulting in a heating power and an efficiency of the device increasing as the cycles of operation to reach the temperature of maximum heating "T High" of the magneto-caloric element 4a at which the temperature of the coolant will stabilize.

Best way to realize 1 invention:

The device 1b of FIG. 3 is substantially similar to the previous one. It differs in that it comprises two magneto-caloric elements 4b, 4c, connected together by the heat transfer fluid circuit 5 in series, these magneto-caloric elements 4b, 4c can have substantially similar magnetocaloric characteristics or different. The magneto-caloric elements 4b, 4c can also be connected to each other in parallel or in a series / parallel combination. It is also possible to provide groups of magnetocaloric elements, these groups being connected together in series, in parallel or in a series / parallel combination. The device 1b and the method are thus easily scalable.

Each magneto-caloric element 4b, 4c is biased by an electromagnet 2b, 2c connected to a separate power supply 3b, 3c, these power supplies 3b, 3c being controlled by one or more control units (not shown). It is thus possible to generate separately, for each electromagnet 2b, 2c, electrical pulses 9b, 9c, simultaneously or successively, with or without overlap period of these electrical pulses 9b, 9c. This configuration makes it possible to combine the magneto-caloric properties of several magnetocaloric elements 4b, 4c, which is particularly advantageous when they are different. The operation of such a device 1b is described with reference to the graph of FIG. 4 which illustrates, in the form of hatched surfaces, the temperature ranges P1, P2, P3 accessible by successively using: a first magnetocaloric element 4b alone to obtain the range of PI temperature between θlMax and θlmin, a first magneto-caloric element 4b and a second magnetocaloric element 4c simultaneously to obtain the temperature range P2 between θ2Max and Θ2min, the second magneto-caloric element 4c alone to obtain the range of P3 temperature between θ3Max and 03min. Thus, by combining the different magneto-caloric properties of the first and second magnetocaloric elements, it is possible to cover a very large total temperature range P located between λmax and Θ3min.

The device of Figure 5 is substantially similar to the device of Figure 1. It differs in that it comprises a heat exchanger "mixed" 78 to successively transfer the calories and frigories.

The method using this device is described with reference to the curves "Curve" I and temperature "Curve θ" of the heat transfer fluid of Figures 6A and 6B, respectively according to modes "cooling" and "heating". This method is substantially similar to that of the device of Figure 1 illustrated in Figures 2A and 2B.

The operation in "cooling" mode illustrated in FIG. 6A differs mainly from that of FIG. 2A in that, since there is only one heat exchanger 78, there is no switching and the heat exchanger 78 remains permanently connected to the magneto-caloric element 4a to successively transfer the calories then the frigories. The operation therefore only has the following three steps for each cycle n: Step 1 - cycle n: Electric pulse 9a, heating of the coolant to a temperature θln (temperature step 1 cycle in progress), higher than the temperature ΘOn of starting or at the temperature Θ4n-1 (temperature step 3 previous cycle) and the temperature Θln-l (temperature step 1 previous cycle). Transfer of the calories by the heat exchanger 78. Step 2 - cycle n: After the electric pulse 9a, heating of the coolant under the inertia of the magneto-caloric heating effect, up to a temperature Θ2n (temperature step 2 cycle in progress) greater than the temperature θln (temperature step 1 cycle in progress) corresponding to the maximum temperature of the heat transfer fluid during this cycle n, and greater than the temperature Θ2n + 1 (temperature step 2 next cycle) corresponding to the temperature maximum heat transfer fluid during the next cycle. Transfer of the calories by the heat exchanger 78. Stage 3 - cycle n: Magneto-caloric effect cooling at the end of the inertia of the effect of 1 heating magnetocaloric inertia, magneto-caloric cooling effect. Cooling of the heat transfer fluid to a temperature Θ3n (stage temperature 3 cycle in progress) lower than the temperature ΘOn and corresponding to the flow temperature of the heat transfer fluid of this cycle n. Transfer of calories then frigories by the heat exchanger 78. Detection of the impulse setpoint In and supply of the electromagnet 2a by a new electrical pulse 9a.

The operation in "heating" mode illustrated by FIG. 6B differs from that of FIG. 2B in that the magneto-caloric cooling effect is not used. Indeed, the pulse parameter In is set so that 1 electric pulse 9a is generated before the temperature Θ3n is lower than the temperature ΘOn. The operation therefore only has the following three steps for each cycle n: Step 1 - cycle n: Electric pulse 9a, heating of the coolant to a temperature θln (temperature step 1 cycle in progress), higher than the temperature ΘOn of starting or at the temperature Θ3n-1 (temperature step 3 previous cycle) but lower than the temperature θln-l (temperature step 1 previous cycle). Transfer of the calories by the heat exchanger 78. Step 2 - cycle n: After 1 electric pulse 9a, heating the heat transfer fluid under 1 inertia of the magneto-caloric heating effect, up to a temperature Θ2n (temperature step 2 cycle in course) greater than the temperature θln (temperature stage 1 cycle in progress) corresponding to the maximum temperature of the coolant during this cycle n, but lower than the temperature Θ2n + 1 (temperature step 2 next cycle) corresponding to the maximum temperature of the coolant during the next cycle. Transfer of the calories by the heat exchanger 78. Stage 3 - cycle n: Magneto-caloric effect cooling at the end of 1 inertia of the effect of 1 heating magnetocaloric inertia, magneto-caloric cooling effect. Cooling of the heat transfer fluid to a temperature Θ3n (stage temperature 3 cycle in progress) greater than the temperature ΘOn and corresponding to the flow temperature of the heat transfer fluid of this cycle n. Transfer of calories then frigories by the heat exchanger 78. Detection of the impulse setpoint In and supply of the electromagnet 2a by a new electrical pulse 9a. In general, in these examples, the magnetic element 2a-c and the magneto-caloric element 4a-c are fixed relative to one another. It is nevertheless possible to provide them mobile. It is also possible to use a greater number of magneto-caloric elements 4a-c and / or electromagnets 2a-c and / or heat exchangers 7, 8, 78.

According to other non-illustrated embodiments, it is possible to use a plurality of heat exchangers 7, 8, 78 or groups of heat exchangers connected to the heat transfer fluid circuit in series, in parallel or in a series / parallel combination. The device la-c and the method are thus easily scalable.

Possibilities of industrial application:

This device la-c and this method can be used for any industrial or domestic application of cooling, heating, air conditioning, tempering.

This description clearly demonstrates that the device la-c and the method according to the invention make it possible to meet the objectives set. In particular, they make it possible to overcome any sealing problem inherent in devices comprising magneto-caloric elements and / or electromagnets or other magnetic means that are movable relative to one another.

In addition, they are very simple in design and require no means of movement to move the magneto-caloric elements 4a-c and / or the electromagnets 2a-c. They are therefore low energy consumers and require a limited number of parts and mechanical parts resulting in reduced maintenance and limited risk of breakdowns. The present invention is not limited to the embodiments described but extends to any modification and variation obvious to a person skilled in the art while remaining within the scope of protection defined in the appended claims.

Claims

claims

1. Device (la-c) for generating magnies with magneto-caloric material comprising at least one magnetic element (2a-c) intended to generate a magnetic field, at least one magneto-caloric element (4a-c) intended to be alternately subjected to said magnetic field for generating calories and frigories, at least one coolant circuit (5) at least a portion of which is disposed in the immediate environment of said magnetocaloric element (4a-c) so as to recovering at least a portion of said calories and / or frigories emitted, said circuit (5) being coupled to circulation means (6) and to at least one heat exchanger (7, 8, 78) arranged to transfer at least one part of said calories and / or frigories recovered by said coolant, characterized in that said magnetic element is an electromagnet (2a-c) coupled to at least one power supply (3a-c) servocontrolled by at least one solid control unit (20) arranged to generate electrical pulses (9a-c) so as to create a pulsed magnetic field, these electrical pulses (9a-c) of intensity I, of duration t and of frequency T being triggered as a function of at least one predetermined pulse parameter, said device comprising at least one thermal sensor (10) arranged to determine the temperature of said heat transfer fluid, this fluid temperature defining at least one pulse parameter.

2. Device (la, lb) according to claim 1, characterized in that said recovery means comprise at least two heat exchangers (7, 8) connected to said circuit (5) in series, in parallel or in a series / parallel combination .

3. Device (la, lb) according to claim 2, characterized in that said recovery means comprise at least one heat exchanger of calories (7) arranged to transfer the calories and at least one heat exchanger of frigories (8) arranged to transfer the frigories, said heat exchangers (7, 8) being coupled to switching means (11) controlled by a control unit arranged to successively connect each heat exchanger (7, 8) to said magnetocaloric element (4a-c) as a function of at least one predetermined switching parameter.

4. The device (la-c) according to claim 1, characterized in that said control unit is arranged so that said frequency of T is in the range 60 seconds and l / ^150th of a second and preferably less than 2 seconds.

5. Device (la-c) according to claim 1, characterized in that said control unit is arranged so that the ratio T / t is between 10 and 100,000, and preferably greater than 1,000.

6. Device (la-c) according to claim 1, characterized in that said control unit is arranged so that said intensity I generates, in said magnetic element, a magnetic field between 0.05 Tesla and 10 Tesla, and preferably greater than 2 Tesla.

7. Device (la-c) according to claim 1, characterized in that said control unit comprises means for adjusting at least one of the parameters of the pulse selected from the group comprising the duration t, the frequency T Intensity I.

8. Device (la-c) according to any one of claims 1 or 3, characterized in that said control unit comprises timing means arranged to determine the time interval elapsed since the switching and / or 1 electrical pulse (9a -c) preceding, this time interval defining at least one switching parameter and / or pulse.

9. Device (la-c) according to any one of claims 1 or 3, characterized in that said control unit comprises means for adjusting said switching parameter and / or predetermined pulse.

10. Device (la-c) according to claim 1, characterized in that said recovery means comprise at least one "mixed" exchanger (78) arranged to transfer calories and frigories.

11. Device (lb) according to claim 1, characterized in that it comprises at least two magneto-caloric elements (4b, 4a) connected together in series, in parallel or in a series / parallel combination.

12. Device (lb) according to claim 11, characterized in that said magneto-caloric elements (4b, 4a) have different magneto-caloric characteristics.

13. Device (lb) according to claim 11, characterized in that it comprises at least two electromagnets (2b, 2c), each associated with a magneto-caloric element (4b, 4a) and at least two power supplies (3b, 3c) arranged to electrically supply said electromagnets (2b, 2c) in a dissociated manner.

14. Device (la-c) according to claim 1, characterized in that the core of said magnetic element (2a-c) is made of a magnetic material with high remanence.

15. Device (la-c) according to claim 1, characterized in that said magnetic element (2a-c) and said magneto-caloric element (4a-c) are fixed relative to each other.

16. A method for generating magneto-caloric material thermoses in which at least one magneto-caloric material element (4a-c) is subjected to at least one electromagnet (2a-c) powered by electrical pulses so as to creating a pulsed magnetic field for generating calories and frigories, recovering at least a portion of said calories and / or said frigories generated by said magnetocaloric element (4a-c) by means of a coolant, is circulated in at least a circuit (5) having at least a portion in the immediate environment of said magneto-caloric element (4a-c) and transferring at least a portion of said calories and / or frigories by means of at least one heat exchanger ( 7, 8, 78), said current impulses (9a-c) of intensity I, of duration t and at a frequency T being triggered as a function of at least one predetermined pulse parameter, the temperature of the said heat transfer fluid and this fluid temperature is used as a pulse parameter.

17. The method of claim 16, characterized in that one uses at least two heat exchangers that are connected to said circuit (7, 8) in series, in parallel or in a series / parallel combination.

18. A method according to claim 17, characterized in that at least one heat exchanger (7) is used to transfer the calories and at least one heat exchanger (8) to transfer the frigories that are connected alternately to the magneto-caloric element (4a-c) as a function of at least one predetermined switching parameter.

19. The method of claim 16, characterized in that is adjusted to the least one of said pulse parameters selected from the group comprising the frequency T so that it ranges between 60 seconds and l / ^150th of second and preferably less than 2 seconds, the ratio T / t is between 10 and 100,000, and preferably greater than 1,000, said intensity I so that it generates in said magnetic element has a magnetic field of between 0.05 Tesla and 10 Tesla, and preferably greater than 2 Tesla.

20. Method according to any one of claims 16 or 18, characterized in that one determines the elapsed time interval since the switch and / or the previous electrical pulse (9a-c), and in that one uses this time interval as a switching parameter and / or pulse.

21. The method according to claim 16, characterized in that at least two magnetocaloric elements (4b, 4c) having different magnetocaloric characteristics are used which are connected together in series, in parallel or in a serial / parallel combination.

22. The method as claimed in claim 21, characterized in that at least two electromagnets (2b, 2c), each associated with magneto-caloric element (4b, 4c), and at least two power supplies (3b, 3c), and in that a first magneto-caloric element (4b) is used in successive phases, then a first magnetocaloric element (4b) and a second magnetocaloric element (4c) simultaneously and finally the second magneto-caloric element (4c) alone so as to combine the magnetocaloric properties of the first and second magnetocaloric elements (4b, 4c).